Kallista COMPLETELY outclassed by another champion, she needs help.
Lets cut to the chase, 
can do everything 
does but better. She's just another new champ whose kit is severely under-loaded. Lets take a look.
Passive - Gains attack speed after killing something, does not scale.
Passive - Infinite dashes while attacking, scales with attack speed.
Q - Charge arrow over 4 seconds, slowed while charging.
Q - Instant spear that deals damage.
Even when fully charged, Kallista Q does less damage than Varus's instant Q. It also has double the CD and more mana cost.
W - Passive - applies maximum 3 Blight stacks to target, can be triggered through hitting a skill shot. Deals up to 15% max health.
W - Passive - If Varus and his tethered ally attack the same target, deal % max health damage. Active - throw out moving wards.
Kallista's passive has no active, and she often relies on a lucky snipe with q or e. Varus has safety through vision, (even though hes likely to escape a gank due to his high mobility), but also the ability to have a nearby ally be a constant threat.
E - Lay down a small circle that slows enemies and reduces healing inside.
E - Rip spears from targets; dealing damage, slowing each, and refunding mana/cooldown if it kills.
Varus's E is almost Kallista's E and W combined. However while Kallista has to hit a skill shot to proc her damage, Varus can simply hit E at any time.
R - Fire a projectile that roots its first target and spreads to nearby enemies after a few seconds.
R - Make an ally invulnerable. Ally can then dash to targeted location, stopping at the first target and instantly knocking up all nearby enemies.
Varus' R also has a longer range and shorter cooldown than Kallista's.
TLDR: I swapped Kallista with Varus and showed how Varus' kit is a gimped version of Kallista's.
